It is to be understood that the description in this part only provides some background information relating to the present disclosure, which may or may not constitute a so called prior art.
Nowadays, a lithium ion battery is known as a green chemical power source. Compared with conventional nickel-cadmium batteries and conventional nickel hydrogen batteries, the lithium ion battery has many advantages such as higher voltage, longer cycling life and higher energy density. Ever since the Japanese company Sony launched the first generation lithium ion batteries, lithium ion batteries have been developed rapidly and applied in kinds of portable devices. The negative electrode in the conventional lithium ion battery comprises graphite carbon material. However, the theoretical specific capacity of the carbon material is about 372 mAh/g. Therefore, further improvement of the capacity of the lithium ion battery is restricted.